Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/08—Muscles; Tendons; Ligaments
  • A61F2/0811—Fixation devices for tendons or ligaments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/08—Muscles; Tendons; Ligaments
  • A61F2/0811—Fixation devices for tendons or ligaments
  • A61F2002/0817—Structure of the anchor
  • A61F2002/0841—Longitudinal channel for insertion tool running through the whole tendon anchor, e.g. for accommodating bone drill, guidewire
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/08—Muscles; Tendons; Ligaments
  • A61F2/0811—Fixation devices for tendons or ligaments
  • A61F2002/0847—Mode of fixation of anchor to tendon or ligament
  • A61F2002/0858—Fixation of tendon or ligament between anchor and bone, e.g. interference screws, wedges
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
  • A61F2/30771—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth applied in original prostheses, e.g. holes or grooves
  • A61F2002/3085—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth applied in original prostheses, e.g. holes or grooves with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
  • A61F2002/30858—Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2240/00—Manufacturing or designing of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
  • A61F2240/001—Designing or manufacturing processes
  • A61F2240/002—Designing or making customized prostheses
  • A61F2240/004—Using a positive or negative model, e.g. moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

• the invention relates to an interference screw, in particular an interference screw for the endosteal fixation of a ligament, in particular a replacement ligament of a cruciate ligament.
• Interference screws for medical applications are known. These are screws, which are screwed into a previously set hole or a medullary canal and are fixed after screwing by an interference fit in the channel.
• Such a generic interference screw shows, for example, the German utility model DE 9320384.
• the invention is the object of the invention to provide an interference screw, which is less prone to loosen.
• Another object of the invention is preferably to be able to produce a bioresorbable screw made of a metal alloy by die-casting, wherein the screw has no sharp edges at
• the invention relates to an interference screw with an external thread, so a screw which is stuck due to an oversize in a borehole or bone canal.
• the interference screw for fixing a ligament, in particular a Wienbandligêts is formed.
• the threads of the external thread at least partially recesses.
• recesses which are preferably formed as a flattening in the threads, are effective for preventing rotation.
• the recesses are arranged one behind the other in the axial direction.
• the recesses are preferably formed as flattenings of at least the tooth base, whereas the tooth heads are preferably not provided with flats.
• a flattening is understood to be any material removal in the tooth base over a certain angle range from the remaining circumference of the thread.
• At least half of the one recess Preferably, at least half of the one recess. So a good effect is ensured as anti-rotation.
• the recesses form at least in sections a secant surface to the tooth flank and to the tooth base of the Thread.
• the secant surface preferably runs along a recess projecting into the tooth flanks and the tooth base and, before reaching the tooth head, strikes the tooth flanks.
• the tooth heads of the thread are thus not covered by the recess. Rather, in a preferred embodiment of the invention, the recess is formed solely by a flattening of the threads.
• the secant surface preferably runs along lines tangential to the screw, ie it is straight so that a tangent of a circle whose center lies on the central axis of the interference screw lies essentially on the surface of the recess.
• the secant surface which has just been formed in a tangential direction makes it easier to remove the screw in a die-casting process.
• the recess penetrates at the lowest point on the tooth base of the
• Thread between 0.05 and 1 mm in the screw body, while it tapers on the flanks of the thread in the direction of the tooth head and still spreads on the flanks of the teeth from the screw body.
• the recess occupies only a portion of the screw body, preferably the recess occupies an angle of less than 50 °, more preferably less than 40 °, in the thread. This angle is understood to be the angle at which the furthest points of a recess lie apart in one thread. In the axial direction is preferably substantially provided the entire thread with recesses. Only on a tapered screw head no recesses are provided in a further embodiment of the invention.
• the interference screw on an inner channel, preferably to receive a guide wire or guide pin.
• the interference screw is formed from a bioresorbable material.
• a magnesium die cast alloy is suitable for this purpose.
• the thread of the screw in a preferred embodiment of the invention has a pitch between 2 and 3 mm. This slope has proven particularly suitable for screwing into bone material.
• a sawtooth profile in particular makes it easy to screw in the screw while at the same time allowing good fixability.
• the flanks on the front side of the thread that is, the insertion direction facing edge, at an angle between 25 ° and 35 ° to a plane perpendicular to the central axis of the screw plane, whereas the flanks on the back at a smaller angle to a vertical to the central axis of the screw extending plane of 10 ° to 20 ° stand.
• the tooth heads of the thread are rounded.
• flank diameter to the core diameter 1.4 to 1.8, more preferably from 1.5 to 1.6 has been found to be particularly suitable.
• Fig. 1 shows a three-dimensional side view of a schematically illustrated embodiment of an interference screw
• Fig. 2 shows a sectional view along the
• Fig. 4 shows a detailed view of the recess
• Fig. 5 and 6 show schematically manufacturing steps of a die-casting method for an interference screw.
• Fig. 1 shows a three-dimensional side view of an interference screw.
• the interference screw 1 comprises a screw body with a substantially sawtooth-shaped thread 2. At the top, the thread tapers. Furthermore, the screw body has a channel 5, by means of which the interference screw can be centered on a wire or a mandrel.
• the threads 4 of the interference screw have recesses 3, which extend substantially over the entire length of the screw.
• the recesses 3 are each formed as secant surfaces, which coat the flanks of the teeth of the screw in the screw body, reach the tooth bottom, the substantially lowest point and on the opposite side again stroke out of the flank.
• Fig. 2 shows a sectional view of the interference screw 1 shown in Fig. 1 can be seen, the channel 5, which extends over the entire length of the screw. Based on this drawing, the definition of the different areas of the thread will be explained in the first place.
• the thread consists of teeth which have a front flank 7, a rear flank 8 and a tooth head 6 and a tooth base 9.
• the recess (not shown in this view) sweeps out of the screw body substantially shortly before reaching the tooth head 6.
• Fig. 3 in which a front view is shown on the back of the interference screw 1.
• the recesses 3 substantially not tapered.
• the screw on the back for example, a hexagon 10 or a Torxantrieb (not shown).
• the recesses 3 it was possible to achieve virtually no protrusions in the case of an interference screw 1 produced by diecasting from a magnesium alloy. Furthermore, the recesses 3 also serve as anti-rotation.
• FIG. 4 shows a detailed view of an interference screw in the region of a recess 3, which is shown as a black surface.
• the recess formed as a secant surface is tangent to a circle having its center in the axis of the screw.
• a secant surface recess 3 along a guide curve which dips on a flank in the screw body, reaches the lowest point on the tooth base and on the opposite side strokes out of the screw body.
• the interference screw 1 is manufactured by means of a die casting process.
• the at least still viscous melt is pressed into a mold having an upper part 12 and a lower part 11, shown here schematically in a sectional view.
• the metal the
• Touching walls of the mold forms a skin that leads to the beneficial closed surface.
• a porous structure can be provided inside the interference screw. It is believed that this porous structure is caused by gas inclusions or by shrinkage of the metal while the material solidifies within milliseconds. It has been found that such a porous structure, which is normally undesirable in die casting, brings about the described advantageous properties.
• the mold is opened.
• the opening direction is shown by the arrow 13.
• the recesses 3 of the interference screw 1 preferably do not run exactly parallel to the opening direction, but at a small angle of 0.1 to 3 °. The method enables a rapid production of an interference screw with significantly improved properties, in particular with regard to the degradation of the screw in the tissue.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Cardiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• Rehabilitation Therapy (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Rheumatology (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Mechanical Engineering (AREA)
• Surgical Instruments (AREA)
• Prostheses (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (1)

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Citations (7)

Family Cites Families (3)

• 2008
  • 2008-08-11 DE DE102008037202.1A patent/DE102008037202B4/de not_active Expired - Fee Related
• 2009
  • 2009-08-11 EP EP09777807.0A patent/EP2313028B1/de not_active Not-in-force
  • 2009-08-11 WO PCT/EP2009/005819 patent/WO2010017960A1/de not_active Ceased
  • 2009-08-11 ES ES09777807.0T patent/ES2638363T3/es active Active

Patent Citations (7)

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